igneous
Porphyry
Porphyritic Igneous Rock
AI-generated identification · may be incorrectHardness of 6-7 on Mohs scale, variable colors including reddish-brown with contrasting lighter crystals, dull to sub-vitreous luster, and aphanitic groundmass with distinct larger phenocrysts.
Identified More igneous →
Explore Porphyry in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 6-7 on Mohs scale, variable colors including reddish-brown with contrasting lighter crystals, dull to sub-vitreous luster, and aphanitic groundmass with distinct larger phenocrysts.
Formation & geological history
Formed via a two-stage cooling process where magma cools slowly deep underground to form large crystals, then rapidly erupts near the surface.
Uses & applications
Historically used in monumental architecture and sculpture; currently used as decorative crushed stone and construction aggregate.
Geological facts
Imperial Porphyry was highly prized by Roman emperors for its deep purple-red color, symbolizing royalty.
Field identification & locations
Identify by its distinct large crystals embedded in a fine-grained matrix. Commonly found in volcanic regions worldwide.
